Thread: random functions

The following code has two random functions that don't pick random. THEY ALLWAYS PICK 0!!!!can anyone help me???

<near the bottem>



#include <iostream.h>
#include <conio.h>
#include <stdlib.h>
int main()
{
clrscr();
int tries;
int x;
int y;
int a = 0;
int b = 0;
int plyrs;
cout<<"how many players?<2 for 2 and anything for 1>"<<endl;
cin>>plyrs;
if (plyrs==2)
{
cout<<"please enter amount o' tries: "<<endl;
cin>>tries;
clrscr();
cout<<"hider, type coordinates of hidden character:<has to be under 10,10 please."<<endl;
cin>>x>>y;
clrscr();
cout<<"seeker, you are at coordinates 0,0. you will have to find the hidden character in 15 tries. move up down left and right. good luck."<<endl;
getch();
clrscr;
{
int c = 0;
while(c==0)
{
if (tries>0)
{
if (b==x&&a==y)
{
cout<<"congratulations!you've found the hidden item!!!!"<<endl;
getch();
return 0;
}
else
{
clrscr();
cout<<"coordinates="<<b<<", "<<a<<endl;
cout<<"you have "<<tries<<"tries left."<<endl;
gotoxy(b, a);
char cl = getch();
if (cl==72)
{
gotoxy(b, a);
putch('$');
gotoxy(b, a++);
tries=tries-1;
}
if (cl==104)
{
if (tries<=10)
{
cout<<"first coordinate is: "<<x<<endl;
getch();
}
}
if (cl==80)
{
gotoxy(b, a);
putch('$');
gotoxy(b, a--);
tries=tries-1;
}
if (cl==63)
{
cout<<"its not nice to cheat but, oh well. the coordinates are: "<<x<<", "<<y<<endl;
getch();
}
if (cl==77)
{
gotoxy(b, a);
putch('$');
gotoxy(b--, a);
tries=tries-1;
}
if (cl==75)
{
gotoxy(b, a);
putch('$');
gotoxy(b++, a);
tries=tries-1;
}
if (cl==27)
{
getch();
return 0;
}
}
}
else
{
cout<<"im sorry but you ran out of tries!!!"<<endl;
getch();
return 0;
}
}
}
return 0;
}
else
{
cout<<"ok, computer. the computer will now detirmine the coordinates...."<<endl;
int x = rand()%16;//RANDOM OUT OF 15!!!!
int y = rand()%16;//RANDOM OUT OF 15!!!
cout<<"the coordinates are out of 15."<<endl;
clrscr();
cout<<"how many tries?"<<endl;
cin>>tries;
clrscr();
{
cout<<"you have "<<tries<<" tries to guess the coordinates."<<endl;
cout<<"your coordinates are: "<<a<<", "<<b<<endl;
if (tries>0)
{
int d =5;
while(d==5)
{
if (b!=x, a!=y)
{
char cl = getch();
if (cl==72)
{
gotoxy(b, a);
gotoxy(b, a++);
tries=tries-1;
}
if (cl==80)
{
gotoxy(b, a);
gotoxy(b, a--);
tries=tries-1;
}
if (cl==75)
{
gotoxy(b, a);
gotoxy(b--, a);
tries=tries-1;
}
if (cl==77)
{
gotoxy(b, a);
gotoxy(b++, a);
tries=tries-1;
}
if (cl==104)
{
if (tries<=10)
{
cout<<"the hint is: "<<x<<" is the first coordinet"<<endl;
}
}
else
{
cout<<"congratulations!!! you found the right coordinates!!"<<endl;
}
}
}
}
else
{
cout<<"sorry, but tries ran out!!"<<endl;
}
}
}
return 0;
}


Please help me if you can!!!

You have to seed the rand() function using srand() if you want it to produce a different series of random numbers everytime your code is run, check the FAQ.

The rand function produces a random number at compile time, therefore to get a random number each time you execute your program you would need to re-compile it, not very good. However you can use the function srand to seed the rand function, for example you can base the rand function on the time, therefore producing a different number each time.

Code:

int stime;
long ltime;

ltime = time(NULL);
stime = (unsigned) ltime/2;
srand(stime);

printf("%d", rand()%16);

This time you should get a different number each time.

The rand function produces a random number at compile time, therefore to get a random number each time you execute your program you would need to re-compile it

I don't think it makes any difference when it's compiled, rand() will take a default seed value and this won't be influenced by when it's compiled.

have you guys tried my game?? i like it.

ok I said you could have my code if you posted yours so here goes.... sorry about the length but I dont have a zip util on me at the mo so I will cut and paste.

Code:

Board.h

#ifndef BOARD_H
#define BOARD_H


class Board
		{
			private:
						char TheBoard [10][10];
						int HurkleX;
						int HurkleY;

						void Miss(int,int);
						void Hit();
						void Display(int,int)const;
						void Win(int,int)const;
						char* Direction(int,int)const;
			public:
						Board();
						~Board() {}
						void Play();
						
		};

#endif

Code:

Board.cpp

#include "Board.h"
#include "ScreenFuncs.h"
#include <iostream>
#include <ctime>
#include <cstdlib>
#include <cctype>

using namespace std;


Board::Board()
		{
			srand ((unsigned)time(NULL));
			HurkleX=rand()%10;
			HurkleY=rand()%10;
			for (int i=0;i<10;i++)
				for(int j=0;j<10;j++)
					TheBoard [i][j]='.';
		}

void Board::Miss(int x,int y)
		{
			TheBoard [y][x]='X';
			gotoxy(2,20);
			cout<<"Missed the Hurkle but he's "<<Direction(x,y)<<" from there.          "<<flush;
		}

void Board::Hit()
		{
			TheBoard [HurkleY][HurkleX]='H';
		}

void Board::Win(int x,int y)const
		{
			gotoxy(x,y);
			cout<<"You have won!!!! You found the Hurkle!!!!          "<<endl;
		}

void Board::Display(int x,int y)const
		{
			gotoxy(x,y);
			cout<<"  0  1  2  3  4  5  6  7  8  9"<<flush;
			y++;
			gotoxy(x,y);
			for(int i=0;i<10;i++)
			{
				cout<<i<<" "<<flush;
				for(int j=0;j<10;j++)
				{
					cout<<TheBoard[i][j]<<"  ";
					if (j==9)
					{
						cout<<flush;
						y++;
					}
				}
				gotoxy(x,y);
			}
		}

void Board::Play()
{
	int Tries=10,x=0,y=0;
	
	do
	{
		Display(2,2);
		gotoxy(2,14);
		cout<<"Where do you think the Hurkle lies...."<<endl<<"  Enter X Position (0-9) ?      \b\b\b\b\b";
		cin>>x;
		cout<<"  Enter Y Position (0-9) ?      \b\b\b\b\b";
		cin>>y;
		if (x<0 || x>9)continue;
		if (y<0 || y>9)continue;
		if (x==HurkleX && y==HurkleY)
		{
			Hit();
			Display(2,2);
			Win(2,20);
			break;
		}
		else
		{
			Miss(x,y);
		}

		Tries--;
		gotoxy(2,18);
		cout<<"Tries left = "<<Tries;
	}
	while(Tries);
	if (x==HurkleX && y==HurkleY) return;
	gotoxy(2,20);
	cout<<"Sorry you have lost.Better luck next time.        "<<endl<<"  The Hurkle was at X-Pos :- "<<HurkleX<<" and Y-Pos :- "<<HurkleY<<endl;
}			

char* Board::Direction(int x,int y)const
{
	int DistX=(HurkleX-x);
	int DistY=(HurkleY-y);
	if(abs(DistX)>abs(DistY))
		if (DistX < 0)
			return "LEFT";
		else return "RIGHT";
	if(abs(DistX)<abs(DistY))
		if (DistY < 0)
			return "UP";
		else return "DOWN";
	if (abs(DistX)==abs(DistY))
	{
		int a=rand()%2;
		if (a)
		{
			if (DistX < 0)
			return "LEFT";
		else return "RIGHT";
		}
		else
		{
			if (DistY < 0)
			return "UP";
		else return "DOWN";
		}
	}
}

Code:

ScreenFuncs.h

void clrscr();
void gotoxy(int,int);

Code:

ScreenFuncs.cpp

#include <windows.h>
#include "ScreenFuncs.h"

// clearscreen function

void clrscr()
{
   COORD coordScreen = { 0, 0 };
   DWORD cCharsWritten;
   CONSOLE_SCREEN_BUFFER_INFO csbi;
   DWORD dwConSize;
   HANDLE hConsole = GetStdHandle(STD_OUTPUT_HANDLE);

   GetConsoleScreenBufferInfo(hConsole, &csbi);
   dwConSize = csbi.dwSize.X * csbi.dwSize.Y;
   FillConsoleOutputCharacter(hConsole, TEXT(' '), dwConSize, coordScreen, &cCharsWritten);
   GetConsoleScreenBufferInfo(hConsole, &csbi);
   FillConsoleOutputAttribute(hConsole, csbi.wAttributes, dwConSize, coordScreen, &cCharsWritten);
   SetConsoleCursorPosition(hConsole, coordScreen);
}

// gotoxy function

void gotoxy(int x, int y) 
{ 
    COORD point; 
    point.X = x; point.Y = y; 
    SetConsoleCursorPosition(GetStdHandle(STD_OUTPUT_HANDLE),point); 
}

Code:

Main.cpp

#include "Board.h"

int main()
{
	Board Game;
	Game.Play();
	
	return 0;
}

Enjoy.